C-nanocoated ZnO by TEMPO-oxidized cellulose templating for improved photocatalytic performance.

Ultrafine C-doped ZnO/carbon nanocomposites with different photocatalytic activities have been prepared using TEMPO-oxidized cellulose as a template but also as the source of carbon. The result is an enhancement of the photocatalytic activity ascribed to different phenomena: a high mesoporosity beneficial to mass transport, a thin carbon layer onto ZnO increasing the charge transfer and hydrophobicity of ZnO, a narrowing of ZnO band gap and an increase of the zinc (VZn) and oxygen (Vo) vacancies effectively suppressing of the charge recombination. These are evidenced by photocatalytic test of photodegradation of methyl orange (MO) achieved to assess and compared the different photocatalysts. The highest rate constant value of photodegradation of MO is 0.0254 min-1, three times higher than that of ZnO prepared without templates (0.0087 min-1). The present results introduce a new vision of the use of template with multiple roles in the preparation of inorganic materials and specially photocatalysts.